1. Field of the Invention
The present invention is directed to a combustion-operated setting device, and more specifically, to a setting device having control circuitry to reduce the effects of electromagnetic interference from an ignition device for generating an ignition spark to ignite fuel in the combustion chamber of the setting device.
2. Description of the Prior Art
Setting devices typically have a combustion chamber in which a portion of liquid gas or other vaporizable fuel can be burned with an oxidizing agent such as, e.g., the surrounding air. A setting piston which is displaceably guided in a piston guide is driven by the combustion energy to drive a fastener into an object.
U.S. Pat. No. 6,123,241 discloses a combustion-operated setting device which has an electronic control with a microprocessor for controlling ignition and injection. The setting device includes various sensors for measuring the atmospheric pressure and the fuel pressure. The apportioning and metering of the fuel from the fuel reservoir to the combustion chamber is controlled by a microprocessor based on the data acquired by the sensors. The microprocessor cooperates with a monitoring valve for monitoring the fuel.
The combined ignition and injection electronics disclosed in U.S. Pat. No. 6,123,241 are disadvantageous in that the electromagnetic compatibility (EMC) emission of the ignition spark can cause interference which affects the combined electronics in their entirety and, for example, can also influence a subsequent new injection of fuel.